| Mechanical energy is the most common energy in daily life.It is always produced in walking,movement and other states.Collecting this part of energy can be used to drive wearable electronic devices.Considering the sporadic nature of this part of mechanical energy,it is necessary to develop energy conversion and storage systems to store and distribute the collected energy stably and continuously.The self-powered wearable electronics currently developed generally have problems such as insufficient flexibility,poor wearing comfort or low energy collection efficiency.Piezoelectric-triboelectric hybrid generator has the advantages of strong output signal,flexible structure size,low production cost and non-toxic functional materials.Supercapacitors have the advantages of large capacitance,fast charging and discharging speed,long cycle life and high safety,and are easy to realize micro-miniature and flexible integration,becoming the preferred energy storage device for self-powered integrated wearable electronic devices.In this work,a piezoelectric and triboelectric hybrid flexible generator is developed.The influence of triboelectric and piezoelectric on the output signal is discussed,and the piezoelectric enhancement mechanism is deeply studied.Flexible supercapacitors with high capacity and cycle stability were prepared,and the effect of graphene on the performance of electrode materials was discussed.The generator and supercapacitor were integrated and their electrical output performance and wearability were tested.The main research contents and results are as follows:（1）A flexible piezoelectric-triboelectric hybrid generator was developed by using porous Zn O as piezoelectric functional material,polydimethylsiloxane（PDMS）as triboelectric material and silver nanowires（Ag NWs）as conductive filler.The influence of different porous Zn O contents on the electrical output performance of the generator was studied,and the suppression effect of Ag NWs conductive fillers on the piezoelectric potential shielding effect was discussed.The electrical output performance and flexibility of the device were tested.The results displayed that the generator had excellent electrical output performance and long-term stability.It could generate an open circuit voltage of146 V and a short circuit current of 1.1μA at a pressure of 12.5 k Pa.At the same time,it had excellent flexibility and wearability,which could collect the mechanical energy of the human body during normal walking and generate a 60 V voltage output.（2）Mn0.6Zn0.4S@Graphene electrode material was prepared by hydrothermal method,and flexible supercapacitor was prepared with polyvinyl alcohol（PVA）hydrogel as electrolyte.The promotion effect of graphene microsheets on the capacity improvement of electrode material and device stability was discussed.The results show that the energy density of the supercapacitor can reach 58.89 Wh kg-1 at a power density of 800 W kg-1,showing excellent energy storage effect.（3）Using the developed hybrid generator and supercapacitor,a flexible capacity-energy storage integrated device is assembled,and its electrical performance and application performance are tested.The results show that the device can charge the supercapacitor to 0.8 V within 20 s and achieve a current output of 0.4μA.At the same time,the integrated system can collect the mechanical energy generated by human motion,showing good practical application potential. |
